no power from panels?

[UGT]

My system has been up and running for a few months with no problems. Noticed this morning that the controller does not show any input from the panels on the roof. From the on/off switch I took the two -/+ leads coming down from the roof from the panels and tested and only showed 2.3v. Should be at least 24+v. Don't know what has happened but am thinking there's something wrong on the roof.
My sytem is eight 200 watt RichSolar panels on the roof parallel and series connected to my 60amp RichSolar controller to my three 24 volt 200 amp LiTime batteries with 3000 watt inverter. I tested my volt meter with the batteries and showed correctly 26.4 volts just to make sure my meter is working. Stumped. System has been producing regularly 1400 to 1500 watts daily from the panels keeping the batteries charged to 28.6 volts.
We have had some rain last few days but nothing torrential, no high winds, no hail, some distant lightning nothing close to speak of. But have had the same weather off and on last couple months and created no problems.
Can a panel just stop working? How to check the panels? They are all mounted fairly close together with about 4 inch clearance from the roof. I put my eyes on them and saw nothing obvious that would cause the problem. Any help would be appreciated. Thanks, George

 

[MisterSandals]

Almost certainly on of the connections has lost contact.

 

[UGT]

What scenario would cause my in-line 15 amp fuse to blow that is on the positive line on my roof from my panels to my controller inside the house?

 

[MisterSandals]

My sytem is eight 200 watt RichSolar panels on the roof parallel and series connected t

cause my in-line 15 amp fuse to blow

If your parallel panels/strings exceed 15A, that would do it.

What are your panel specs and array configuration? If you're expecting 24V, you probably have 8P or 2S4P.
8P would be (200W / 24V) = 8.3A x 8 = 66.6A
2S4P would be 33.3A

 

[UGT]

Discovered that I had a 30A inline fuse that blew. lt was connected inline on the postive wire from panels on roof to controller. I thought it was a 15A but not. Put in new fuse and everything seems to be working okay as it was previously.

I bought the 1600 watt 24volt solar kit from Rich Solar. It is set up on the roof exactly as per their instructions with the included 30A fuse. I have 8 panels. 4 panels connected in series and another 4 panels connected in series. The two strings are connected to each other parallel. Attached label from back of my panels. Can't figure what would have made the 30A fuse blow.

 

[sunshine_eggo]

Discovered that I had a 30A inline fuse that blew. lt was connected inline on the postive wire from panels on roof to controller. I thought it was a 15A but not.
I have 8 panels. 4 panels connected in series and another 4 panels connected in series. The two strings are connected to each other parallel. Attached label from back of my panels. What size fuse would be appropriate.

Typical answer 1: 1.25X the wire rating.
Typical answer 2: Max fuse rating listed on the panel per string.

Your specific answer:
Isc is 10.2A, so 2P is 20.4A, so at least 10awg wire.
You technically don't need any fuses or breakers in a 2P configuration. If you insist, either 15-20A per string or 30A total.

 

[UGT]

Typical answer 1: 1.25X the wire rating.
Typical answer 2: Max fuse rating listed on the panel per string.

Your specific answer:
Isc is 10.2A, so 2P is 20.4A, so at least 10awg wire.
You technically don't need any fuses or breakers in a 2P configuration. If you insist, either 15-20A per string or 30A total.

Thank you, so my 30A fuse is appropriate. Can't figure why the fuse blew.

 

[UGT]

If my batteries have reached 100% full during the day and I put a load on the system does the controller now only send power straight to the inverter and bypass the batteries? If so, is it possible that the load if it were say 30 amps or so would that cause the 30A inline fuse on my panel array to blow or does it not work that way? Thanks.

 

[sunshine_eggo]

If my batteries have reached 100% full during the day and I put a load on the system does the controller now only send power straight to the inverter and bypass the batteries?

Sorta, and it depends. Load causes voltage to drop, and the controller adds current to keep it at the float voltage. The battery absorbs a little, and the rest goes to the load(s).

If so, is it possible that the load if it were say 30 amps or so would that cause the 30A inline fuse on my panel array to blow or does it not work that way? Thanks.

Your 2P can't put out more than 20.4A. Your controller should never allow current to pass from battery to PV.

 

[UGT]

Sorta, and it depends. Load causes voltage to drop, and the controller adds current to keep it at the float voltage. The battery absorbs a little, and the rest goes to the load(s).



Your 2P can't put out more than 20.4A. Your controller should never allow current to pass from battery to PV.

How could there be a current going through the in-line fuse from the solar panel get to be more than 30 amps and blow that fuse? I am a novice at this and is a bit puzzling.
Don't understand what the function of that fuse would be if the panels could never exceed 20.4 amps with 10 gauge wire which is the gauge wire that came with the kit. I guess the Rich Solar kit included the fuse in case the solar panel configuration was different than 2P. But their installation diagram showed 2P configuration. This system had been working in its current configuration perfectly fine for a coupla months.

I have emailed Rich Solar tech support and haven't yet had a response. Thank you for any info that might shed light on this. George in Austin

 

[peakbagger]

Consumer grade fuses are commodities and there can be variations in quality. That said a crappy/corroded connection somewhere in the system can draw more amperage as the system ages causing a fuse to blow. A thermal camera is real handy to look for hot spots. The factory MC4s usually are pretty good quality and assuming they are daisy chained my guess is look at any field connections like the cables between the panels and the equipment as many contractors make up their own connections. There is also MC 4 compatibility issues between brands of connectors that are rated as MC4 compatible. Frequently the locking tabs may not latch fully and the connector will loosen up. I would also look in any junction boxes and snug up on any connectors with screws (preferably in the dark with headlamp.

 

[UGT]

Consumer grade fuses are commodities and there can be variations in quality. That said a crappy/corroded connection somewhere in the system can draw more amperage as the system ages causing a fuse to blow. A thermal camera is real handy to look for hot spots. The factory MC4s usually are pretty good quality and assuming they are daisy chained my guess is look at any field connections like the cables between the panels and the equipment as many contractors make up their own connections. There is also MC 4 compatibility issues between brands of connectors that are rated as MC4 compatible. Frequently the locking tabs may not latch fully and the connector will loosen up. I would also look in any junction boxes and snug up on any connectors with screws (preferably in the dark with headlamp.

I think this may have been the problem. I checked closer with the fuse and saw that it had arcing marks all around it. The fuse holder had corresponding marks on the the locking tabs that hold the fuse in place. No other marks on the ends of the fuses or elsewhere were noticable. I think the fuse did not come into good contact with the end of the wire part in the fuse holder where the end of fuse makes contact. The photo shows the arcing marks. The marks are all around the one end of the fuse.

Rich Solar has yet to respond from my email to their techs to get their take on it.

 

[peakbagger]

Well I was close in concept but didnt specifically mention bad fuse holder although it could be considered a "field connection" so I will rank it as good but not great guess. Still I think you are on the right path to a solution.

 

[UGT]

Rich Solar replied. Bad fuse all they said.

 

[Tomthumb62]

Rich Solar replied. Bad fuse all they said.

I have these "self-resetting" fuses on my PV to SCC and SCC to BATTERY. I was told by WindyNation who recommended and sold these, that they can self-reset 10-15 times before they no longer work. The only downside to them I can see is if they do blow and then re-set (takes a few minutes to re-set) is unless you're there to notice something is off (or have the fancy data recorded or on the cloud), you might never know when they have blown and re-set.

We have a 30A SCC and so are using 30A self-resetting fuses. I doubt we'll ever see a 30A input or output from our panels or SCC in our setup, but if I do and it starts tripping this fuse, I'd up it to 40A (wiring is 8AWG).

I like these BlueSeas ones better because they come with an insulating cover:

https://www.amazon.com/Blue-Sea-Systems-7155-Electrical/dp/B07B934QV1/ref=psdc_15719731_t1_B006PJI1YW